A typical trailing vehicle, such as four-wheeled trailer or wagon, is equipped with Ackerman steering for its steerable front wheels and the tie-rod for these wheels is connected to a hitch pole by means of which the trailer is towed by a draft vehicle. Conventionally, the steering of the front wheels is limited by right and left stops and, if excessive lateral forces are imposed on the hitch pole after either stop is engaged, serious damage, such as bending or breakage of the pole can result. Situations of this this character occur more frequently in backing of the trailer, because it is in that area that control of the draft and trailing vehicles is somewhat more difficult than in straight-ahead operation.
According to the present invention, the hitch pole is made up of front and rear parts normally disposed in end-to-end relationship for normal pushing and pulling operations as well as for steering and the like within limits in which the steering stops are not encountered with forces likely to be detrimental to the hitch pole and/or its related parts. The hitch pole parts are yieldably held together in normal end-to-end relationship by a spring-loaded device of sufficient loading to maintain the hitch parts operative for towing and backing operations not involving overloading. During excessive steering, which involves excessive lateral swinging of the hitch pole about its vertical pivot to the trailer frame or chassis, one of the stops will be engaged by the rear part, and the spring-loaded device will yield to enable continued lateral swinging of the front hitch pole part without imposing undue forces on the now stopped rear hitch pole part.
It is a feature of the invention to provide the terminal, meeting ends of the hitch pole parts with a junction comprising face-to-face abutting plates disposed transversely and upright as respects the fore-and-aft centerline of the hitch pole considered as a unit. A spring-loaded device normally keeps the plates in face-to-face relationship but this device is yieldable in response to predetermined forces to enable one plate to rock on the other about an upright fulcrum. The relationship between the plates and spring-loaded device is such that right and left fulcra are provided to accommodate lateral swinging and "bending" of the pole at one or the other of the fulcra, depending upon the direction of lateral over-swinging of the pole. The spring-loaded device is calculated to prevent excessive separation of the plates during straight-ahead operation; although, the device can function as a cushion in the event of the occurrence of excessive draft forces.
Further features and objects will appear as a preferred embodiment of the invention is disclosed hereafter.